This invention relates in general to optical switching and, more particularly, to a method and apparatus for effecting movement of a component in an optical switch between two operational positions.
Over the past twenty years, fiber optic technology has evolved very rapidly. One aspect of this evolution has been in the area of optical switching. Optical switching systems generally include optical carriers, such as optical fibers, coupled to optical components that receive, transmit, and otherwise process information in optical signals. The switching components in a fiber optic communication system selectively direct the information carried by the optical signal to one or more optical components.
There are a number of desirable characteristics for an optical switch, including low insertion loss, high isolation (low crosstalk), small size, high repeatability, high reliability, low cost, ability to change states very quickly, and ability to change states with minimal energy consumption. The portion of an optical switch which effects actuation of the switch is one area where existing arrangements have been generally adequate for their intended purposes, but have not been entirely satisfactory in all respects. In this regard, existing actuators tend to exhibit one or more of several disadvantages, such as relatively high cost, and the need for a relatively high supply voltage at all times during operation of the switch. In addition, existing actuators, such as piezoelectric actuators, generally use direct actuation that can impose mechanical constraints on the switch.
From the foregoing, it may be appreciated that a need has arisen for a method and apparatus for optical switching which involves actuation in a manner that avoids some or all of the disadvantages of existing actuators. According to the present invention, a method and apparatus are provided to address this need. In this regard, one form of the present invention includes a first member having a first generator that includes a first pole which can generate a magnetic field, and a second member having a second generator that is adjacent the first generator and that includes a second pole which can generate a magnetic field, the first member being supported for movement relative to the second member between first and second positions. One of the first and second generators includes a polarity control conductor extending adjacent one of the first and second poles therein and the other of the poles in the other of the generators effects generation of a magnetic field of predetermined polarity. When a current is passed in a first direction through the polarity control conductor, the one pole generates a first magnetic field in a manner so that the interaction between magnetic fields generated by the first and second poles causes the first member to be urged toward the first position. When a current is passed through the polarity control conductor in a second direction opposite the first direction, the one pole generates a second magnetic field with a polarity opposite to the first magnetic field, so that the interaction between the magnetic fields generated by the first and second poles causes the first member to be urged toward the second position. A first optical element is coupled to the first member and a second optical element is coupled to the second member. Movement of the first member relative to the second member between the first and second positions effects movement of the first optical element relative to the second optical element respectively between first and second positions. When the first optical element is respectively in the first and second positions thereof, an optical path is respectively established and interrupted, the first and second optical elements each influencing radiation traveling along the optical path when the first and second optical elements are in the first position thereof.